Compositionally-graded and structurally-graded photovoltaic devices and methods of fabricating such devices

Patent metadata

Field	Value
Publication number	US-8962978-B2
Application number	US-95963110-A
Country	US
Kind code	B2
Filing date	Dec 3, 2010
Priority date	Jul 28, 2005
Publication date	Feb 24, 2015
Grant date	Feb 24, 2015

Abstract

A semiconductor structure is described, including a semiconductor substrate and a semiconductor layer disposed on the semiconductor substrate. The semiconductor layer is both compositionally graded and structurally graded. Specifically, the semiconductor layer is compositionally graded through its thickness from substantially intrinsic at the interface with the substrate to substantially doped at an opposite surface. Further, the semiconductor layer is structurally graded through its thickness from substantially crystalline at the interface with the substrate to substantially amorphous at the opposite surface. Related methods are also described.

First claim

What is claimed:

1. A semiconductor structure, comprising:
a doped crystalline semiconductor substrate; and
a semiconductor layer disposed on the doped crystalline semiconductor substrate, the semiconductor layer having a structurally graded region through a first depth from a substantially crystalline state at a lower portion of the structurally graded region to a substantially amorphous state at an upper portion of the structurally graded region,
wherein the lower portion of the structurally graded region is disposed in direct contact with the doped crystalline semiconductor substrate, and wherein the lower portion of the structurally graded region comprises crystals such that the width of the crystals is substantially wider than the thickness of the lower portion.

2. The semiconductor structure, as set forth in claim 1 , wherein the semiconductor layer further comprises a compositionally graded region through a second depth from a substantially intrinsic state at a lower portion of the compositionally graded region to a substantially doped state at an upper portion of the compositionally graded region.

3. The semiconductor structure, as set forth in claim 2 , wherein the structurally graded region and the compositionally graded region at least partially overlap.

4. A photovoltaic device, comprising
a first electrode;
a second electrode; and
a semiconductor structure disposed between the first electrode and the second electrode, the semiconductor structure comprising:
a doped crystalline semiconductor substrate; and
a semiconductor layer disposed on the doped crystalline semiconductor substrate, the semiconductor layer having a structurally graded region through a first depth from a substantially crystalline state at a lower portion of the structurally graded region to a substantially amorphous state at an upper portion of the structurally graded region,

wherein the lower portion of the structurally graded region is disposed in direct contact with the doped crystalline semiconductor substrate, and wherein the lower portion of the structurally graded region comprises crystals such that the width of the crystals is substantially wider than the thickness of the lower portion.

Assignees

• Korevaar Bastiaan Arie
• Johnson James Neil
• Tolliver Todd Ryan
• Kreutz Theodore Carlton
• Zhang Xiaolan
• Gen Electric

Inventors

• Korevaar Bastiaan Arie
• Johnson James Neil
• Tolliver Todd Ryan
• Kreutz Theodore Carlton
• Zhang Xiaolan

Classifications

• H10F77/1662

  including only Group IV materials · CPC title

• H10F77/1642

  including only Group IV materials · CPC title

• H10F10/166

  the Group IV-IV heterojunctions being heterojunctions of crystalline and amorphous materials, e.g. silicon heterojunction [SHJ] photovoltaic cells · CPC title

• H10F10/17

  Photovoltaic cells having only PIN junction potential barriers · CPC title

• H10F10/13

  Photovoltaic cells having absorbing layers comprising graded bandgaps · CPC title